hi guys.I ve got a nice and big lowepro vertex200 backpack (1 body, 4-6 lenses).but what I dislike is if I need to change the lens i have to put it down on the ground(on backside)and open the full backpack to get inside.

-->perfect would be a backpack with upper and lower compartment.a big upper compartment for frequently-used lenses!!and a lower compartment for body, other lenses, accessories...

thanks candyman!yes, I ve seen these kata bags; and you are right these are the best which I found too...but they upper storage is quite small.

I own the Lowepro Flipside 400 AW Black. I have to take it off and laydown to exchange gear. But, this bag has its plusses and for other reasons I bought it.

I have to admit that I don't own the Kata 3N1-2/35L-PL but I do own the Kata 123-GO-30The upper compartment in my Kata can hold the 70-200 f/2.8 MKII but not attached to the camera. I can however put my 6D with the 24-105L attached in that compartment. Advantage is that it does have a side opening. As you saw in the images/video. You swing the bag and open it to exchange gear. Anyway, maybe other people will have some interesting options....

Have you considered a belt system to supplement your backpack? You can keep your most used lenses by your side with easy access. The next best alternative to carrying two bodies. Very convenient in many situations.

The blurb tells me the top is for 'other stuff' with the cameras/lens stored in the base. However, a 7D with Battery Grip & 300/4L will fit comfortably in the top (horizontally), or you could open the top zipper (dividing the top/bottom sections) and make it a genuine top loader.

Packed for action, I keep a camera/lens in the top. For travel it fits the 7D with 300/4L (attached) fully supported in the base, 135/2L, 430 EX flash, 6D, & 24-70/4L separately, plus one spare slot. This then leaves the top compartment completely free.

An iPad mini fits in the pouch on the outside face, and 13" MBA inside a dedicated compartment. Room for a couple of iPhones in one side pocket, and lens/body caps & batteries in the other.

I'm going to try the Protactic 350. I shoot quite a bit in the 'field', 'bush', great outdoors whatnot. I like the idea of it being not too large (one body two medium lenses) and tough as nails. I like my Lowepro Flipside Sport 15L but it has developed tears and snags, not too mention the buckles aren't the most rugged. Also the waist strap is poorly designed.

I don't have much lens/body GAS but the holy grail bag search has me under it's spell.